William l



W. L. VAN KEUREN.

LAMP MANUFACTURE.

APPLICATION FILED JUNE 11. 1918.

1,326,121 Patented Dec. 23,1919.

Fig. l.

Inventor: William JV. Van Kewren,

FIO.

WILLIAM L. VAN KEUREN, OF NORTH BERGEN, NEW JERSEY, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

LAMP MANUFACTURE.

Application filed June 11, 1918.

Hudson, State of New Jersey, have invented certain new and useful Improvements in Lamp Manufacture, of which the following is a specification.

In the sealing-in operation which forms a step in the manufacture of incandescent lamps the bulb is usually held vertical with the neck downward and the stem held with its flare or enlarged portion inside the neck,

, which is considerably larger than the flare and extends some little distance below it. The neck of the bulb is then heated whereupon it decreases in diameter and its walls become somewhat thinner in the heated zone until eventually the neck engages the edge of the flare and is sealed to it. The neck immediately below the flare is then heated to such an extent that the waste portion drops 01f. In a great many-cases the neck does not contract uniformly, in which case the seal may be crooked, or the neck does not become thin enough in the heated zone, and the glass at the joint between the neck and the edge of the flare is so thick that it is apt to crack.

The object of my invention is to provide an improved machine in which the neck of the bulb is elongated in such a manner that the heated glass is thinned out evenly regardless of variations in thickness of the walls of the neck. A further object is to improve the construction of the lamp by holding the neck of the bulb concentric with the stem during the sealing-in operation. A further object is to provlde a machine by means of which a mount having a perforated flare through which the lamp may be exhausted can be sealed into a bulb without the hole being closed up during the sealing-in operation.

In accordance withmy invention, I provide means by which a stress tending to elongate the neck of the bulb is exerted on the neck during the sealing-in operation in such a way that the walls of the neck are thinned. uniformly and drawn down symmetrically to meetthe edge of the flare. I prefer to use a device which rotates with the bulb and holds it centered, and also moves longitudinally of the bulb to pull down the Specification of Letters Patent.

the

Patented Dec. 23, 1919. Serial No. 239,480.

neck of the bulb, thereby thinning out the heated walls of the neck evenly and also pulling off the surplus or waste part of the neck.

For keeping the exhaust hole through the I flare open while sealing in the mount I provide means such as a pin which projects through the hole andprevents its closing up during the sealing-in operation.

y invention will best be understood in connection with the accompanying drawings in which I have shown some of the various forms in which it may be embodied, and in which Figure 1 is a view in elevation of a head for holding the bulb and stem in proper relation to each other with a pulling down device attached to it, the parts being in the position occupiedby them at the beginning of the sealing-in operation; Fig. 2 is a view of the upper part of the sealing-in head shown in Fig. 1 after the neck of the bulb has been elongated and has met the edge of the flare; Fig. 3 is a plan view of-the pulling down device shown in Figs. 1 and 2; Fig. 4 is a plan view of a modified form of this device; Fig. suitable for the manufactuge lamps; and Fig. 6 is an elevation of a stem holder suitable for this type of stem and embodying my invention for keeping the exhaust hole open during the sealing-in operation.

In Fig. 1 of the drawings my invention is shown applied to a" sealing-in machine of the usual type, comprising a horizontal rotatable spider 10 having a number of rota table heads, such as the head 11, for holding the bulb and the stem in proper relation, and brought successively within range of the sealing-in fires indicated by the burner 12. Each head 11 comprises a bulb holder 13 and a stem holder 14, and may be rotated in front of the burner 12, which directs the flame on the neck of the bulb and thereby produces a heated zone at the edge of the flare ofthe stem. The bore of the neck 15 of bulb is considerably greater than the diameter of the flare 16 of the stem.

In accordance with my invention I pro: vide means, such as a pulling down fork 17, for moving verticallydownward during the sealing-in operation and carrying the lower end of the neck of the bulb down with it.

- engage the edge of the In the preferred construction the fork 17 is pivotally mounted on the head 11 by means of an adjustable block 19 in such a position that its free ends or prongs 18 tend to drop erted by the fork 17 causes the neck to decrease m diameter until the heated walls flare 16 and are sealed to it. The sealing-in fires then heat the glass until the wasteportion below the flare is pulled ofl, as indicated in Fig. 2. The fork 17 cannot tilt or twist during its downward movement, so that both prongs move downward the same distance and pull the neck down uniformly, even though the glass is thicker on one side than on the other. At the end of the sealing-in operation after the neck has been pulled down the fork is in substantially the position shown in Fig. 2, where practically all of the waste or surplus portion of the neck has been pulled away from the bulb.

As indicated in Fig. 3, the fingers 18 of the yoke engage opposite sides of the neck of the bulb and accurately position it concentric with the stem holder 12. The neck is usually flared toward the open end so that H the fork cannot drop off, but tends by its weight to pull down the neck as well as to center it.

In the modified form of my invention illustrated in Fig. 4:, I show two forks mounted opposite each other, each consisting of a pivoted bar 21 and a concave member 22 adjustably mounted on the bar 21 by means of a set screw 23. The concave members 22 engage the neck of the bulb to center it and also by their weight elongate it during the sealing-in operation. 7

-While the bulb and stem are bein placed in the sealing-in machine, the for: 17 is turned up on its pivot so as to be out of the way, but before the fires are applied to the neck of the bulb the fork is moved down into the position shown in Fig. 1, for example, where it centers the bulb'and by its weight exerts a constant and steady pull on the neck, so that as soon as the glass softens to the proper extent the fork begins to pull it down. As the fork rotates withthe head there is no relative angular move-- ment between the bulb and the fork and no twisting of the neck.

In the manufacture of tipless lamps which ing the sealing-in operation. In accordance with my invention, I use for-tipless lamps a flare 24: with a notch 25, as illustrated in Fig. 5. During the sealing-in operation the flare is carried on a holder 26 having a conical surface 27 and provided with a projection or pin 28 which extends through the flare and keeps the notch 25 open during 'the sealing-in operation. The notch 25 tends to close up during the sealing-in operation, but the pin 28 maintains an opening throughthe flare, so-that when the lamp is removed from the sealing-in machine there is an exhaust hole of the size of the pin 28 through the flare. The exhaust tube can then be sealed to the flare in register with the exhaust hole. 7 I

What I claim as new and desire to secure by Letters Patent of the United States, is 2- 1. In a machineof the character described the combination with a rotatable head for holding a bulb, and a heater for heating the neck of the bulb, of means rotatable with the head and mounted to engage the neck of the bulb beyond the heated zone, said means and said bulb holder having a tendency to move relatively to each other and longitudinally of the bulb to produce a stress tending to elongate the neck of the bulb.

2. In a' device of the character described the combination with a bulb holder, and

means for heating the neck of the bulb, of

-means mounted on said holder to engage opposite sides of the neck of the bulb and to move to exert a stress tending to elongate the neck.

3. In a machine of the character described,

' the combination with a head for holding a bulb with its neck down, and means for heating the neck alonga zone above its lower end, of a member having fingers for engaging the neck of the bulb below the' heated zone and pivoted on said head to exert by gravity a stress tending to elongate the neck. 4. In a machine of the character described, the combination with a head for holding a bulb and a stem inproper relation, and means for heating the bulb to seal the stem into it, of means movably mounted to rotate at the same speed as the bulb and having a tendency to move longitudinally of the bulb to exert a stress tending to elongate the neck of the bulb. I

5. In a machine of the character described, the combination with a rotatable head for holding a bulb and a stem with the flare of the stem in the neck of the bulb, and a heater for heating the neck of the bulb, of an arm pivoted on said head, with its free end in position to rest on the neck of the bulb below the flare and thereby exert by gravity a stress which tends to elongate the heated portion of the neck.

6. In a machine of the character described the bulb on opposite sides, said fork being the combination with a rotatable head for mounted to have a tendency to exert a stress holding a bulb and a stem with the flare of tending to elongate the neck. 10 the stem in the neck of the bulb, and heater In witness whereof, I have hereunto set 5 for heating the neck of the bulb, of a fork my hand this 29 day of May, 1918.

pivoted on said head and having at its free end two prongs which engage the neck of WILLIAM L. VAN KEUREN. 

